Improvement in methods of and apparatus for separating free sulphur



' 3 Sheets--Sheet 1. S. H. JOHNSON.

1 Method of and Apparatus for Separating Free Sulphur. I N0. 166,279. Patented Aug.3,l875.

[Ina/afar 15mm \x.

MPEmys, PNOTO UTNOGRAPNEIL WASHINGTON be 8.

3 Sheets--Sheet 2. S, H. JOHNSON.

s far S'e'par afing Free Sulphur" Patenfied Aug. 3,1875.

3Sheets--Sheet3. S. H. JOHNSON.

Method of and Apparatus for Separating Free Sulphur N0. 166,27 K933, tented Aug.3 1875.

law, v J71??? J01 2% iwlu u I m UNITED STATES PATENT Orrxon SAMUEL HENRY JOHNSON, OF LEA BANK WORKS, STRATFORD, ENGLAND.

IMPROVEMENT lN METHODS OF AND APPARATUS FOR SEPARATING FREE SULPHUR.

Specification forming part of Letters Patent No. 166,279, dated August 3, 1875; application filed July 13, 1874.

To all whom it may concern carbon as is necessary to dissolve all the sul- Be it known that I, SAMUEL HENRY J OHN- .phur, taking care that an air-cock on the top SON, of Lea Bank Works, Stratford, in the of the extractor is open, so as to permit the county of Essex, England, a subject of the air to be expelled from the receptacle. I next Queen of Great Britain, have invented or disheat the contents of the extractor by means covered new and useful improvements in the of a steamjacket or liquid bath up to the boilmethod .of and apparatus for separating free. ing-point of bisulphide of carbon, keeping it sulphur from substances with which it is in ebullition until the vapors arising there mixed and I, the said SAMUEL HENRY J OHN- from shall have expelled the atmospheric airsoN, do hereby declare the nature of the said an operation which should be made as careinvention, and in what manner the same is to fully and completely as possible. When the be performed, to be particularly described and? bisulphide vapors begin to be evolved at the ascertained in and by the following statement; air-cock, I close it and continue the applicathereof-that is to say: 1 tion of heat until a pressure of a few pounds My invention consists of certain improve to the square inch is indicated. I then draw inents in themethod of and inapparatus used; oii' the solution of sulphur by means of a cock for separating sulphur, by means of the chemiplaced at the bottom of the extractor into an cal agents hereinafter mentioned, from mixopen cistern, in which a few inches depth of tnres containing it in the free state, such as Water is always kept, covering the solution in sulphur ore, or the material known as spent order to prevent evaporation. A pipe from oxide of iron, and of the method of maniputhe cock then delivers the sulphur solution lating the agent employed in such a manner, beneath the level of the water. This cistern as to enable the desired result to be efficiently supplies a still provided with a condenser'and obtained without any undue loss of the chemisuitable receiver, which I call the pure-spirit cal agents during the process. It will be found receiver. I next introduce into the extractor in practice that my improvements so facilitate sufficient bisulphide of carbon to wash out the manipulation as to enable the process to the remainder 9f the sulphur solution, and rebe carried out to commercial advantagean peat the operation, if necessary. These washobject which has not-hitherto been successings are run into another receiver, which I fully obtained. I effect the separation in the call a washings-receiver. In this caseI use manner which I will now describe. the washings for the first treatment of the The chemical agent which I find may be next batch operated upon in the extractor, so most beneficially employed is bisulphide of that it is only necessary to evaporate the carbon, and I proceed as follows: I take a strong solution. suitable quantity of the material to be oper- The sulphur solution obtained by the first ated upon by anyconvenient means, and as treatment with bisulphide of carbon is then this should be thoroughly dry, it is, where evaporated in the still, being heated by means necessary, dried, and is brought to such a state of steam in a jacket on the bottom of the still, of division as is requisite for the complete sountil all or nearly all the bisulphide of carbon lution of the sulphur which is mixed with the is removed. The still is provided with blades material. I put it into a receptacle, which or scrapers, which are kept revolving close to hereinafter is called the extractor, provided the bottom during the latter part of the diswith a filter of linen or cocoa fiber, matting, tillation, so as to facilitate the evolution of or other suitable porous material, on a perfothe bisulphide of carbon by preventing the rated diaphragm or grating near the bottom. I sulphur from forming a mass at the bottom of then hermetically close the extractor. In the the still. extractor I use an agitator, which stirsup the At the close of the process of distillation, I material in the manner hereinafter mentioned. inject steam directly into the still, so as to Through a pipe in the bottom of the receptaexpelthe bisulphide-of-carbon vapor, and recle I then introduce asmuch bisulphide of place it with oneof steam." I then open the is introduced.

still and remove the sulphur. The condensed bisulphide of carbon is available without deterioration for fresh operations.

In order to recover the bisulphide of carbon which remains in the residue of the material operated on which is left' in the extract.- or,.l inject steam at the top of the vessel, so as to permeate the material and displace and evaporate the bisulphide of carbon. The resulting vapors pass from the extractor into the condenser of the still by means of a pipe and cock connected therewith from the bottom of the extractor.

When the whole of the bisulphide of carbon has been vaporized and displaced by the steam,

the extractor is opened and the residuum free bon so mixed would be irrecoverably lost, and

would be carried away from the apparatus;

and from the great density of the bisulphideof-carbon vapor the loss would be considerazble.

Under these circumstances it is expedient to permit as little air as possible to become mixed with the bisulphide-oi carbon vapor in the apparatus, and to eliminate therefrom as much as possible all the air-spaces. It is with thisobject that I introduce the bisulphide of carbon at the bottom of the extractor in the manner above described, so as to float the air out of it through the air-cock without admixture with the bisulphide-of-carbon vapor, and

also displace the remainder of the air in the extractor by the vapor of the bisulphide of carbon produced by the applicationof heat to the extractor, as hereinbefore mentioned.

The high specific gravity of the bisulphideof-carbon vapor permits of the expulsion of the air in an effectual and complete manner without admixture, excepting a very trifling amount at the close of the operation, and with the same object I also permit the temperature of the bisulphide of carbon in the extractor to be raised beyond the boiling-point, so as to drive out the solution of sulphur without permitting air to enter the apparatus.

It is also apparent that the subsequent washing above referred to may be effected without the necessity of opening the air-cock, for the bisulphide-of-carbon vapor will condense on cooling, thus producing a partial vacuum, by means of which the quantity of bisulphide of carbon sufficientfor the purpose With the same object any incondensable vapors passing through the condenser are conducted by means of a pipe into an ordinary gas-holder, free communication with which is permitted to obtain through the condenser during the distillation of the sulphur solution; but it is closed at the termination, before opening the still to remove the sulphur.

At the commencement of each fresh operation of distillation of the sulphur solution, after the first operation has been completed, and before charging the still from the supplycistern, the incondensable mixture of bisulphide-of-carbon vapor and atmospheric air is permitted to flow from the gas-holder, by means of a pipe passing nearly to the bottom of the still, in quantity sufficient to float out all the atmospheric air and replace it with air saturated with bisulphide of carbon, the great densityof the mixture permitting this to be done with facility. When the distillation has commenced this saturated air finds its way back again into the gas-holder ready for another operation. Or, the air in the still may be displaced by steam, which, on condensing, would permit the entr of the bisulphide-ofcarbon solution to be evaporated, and thus dispense with the use of the gas-holder for this purpose; but the employment of a gasholderis better, because it prevents the entry of air during the process of distillation.

In order to raise the bisulphide of carbon from the receivers tothe extractor, I close the receivers hermetically, and maintain them alwaysquite filled with water, which also eliminates the air-spaces. Small overflouncocks at their tops permit the Water to flow out in pro portion as it is displaced by the bisulphide of carbon. Pipes for the passage of the bisulphide of carbon from the receivers to the extractors pass water-tight through the tops of the receivers to nearly their bottoms, and the external ends of the pipes are connected with the extractor.

The flow of the bisulphide of carbon through the pipes is controlled by means of cocks. Vater can be admitted at the top of the receivers by means of cocks or valves attached to a water-pipe, conveying the water under suflicient pressure to force the/bisulphide of carbon from the bottom of the receivers up the pipes into the extractor, the water acting as a liquid piston. I thus force the bisulphide of carbon to a higher level without any me chanical appliances, such as pumps, &c., in direct contact with the bisulphide of carbon, and so avoid loss by leakage and a complicity of joints, \vhich is most desirable in working with bisulphide of carbon. When spent oxide of iron is the substance under treatment I find it necessary to use an agitator in the receptacle, for although the process of lixiviation inv beds by percolation can be effected on the small scale in the laboratory, yet on the large scale I find such an operation to be impracticable, owing to the material being liable to cohere or become consolidated into a block impervi- -duce into the rec a the oxide un -closed the air-cock at .I then agitate the co material to become c residuum of the spent oxi tempting t the finer particles, and the process bec'omes swer the purpose in .agitate the con stop the der these circums ing the 000 forcing out the subsequent washings.

By this treatment, after the we been removed, the evaporation 0 phide of carbon from the residuum by the direct injection of steam at the top of the extractor is rendered practicable, which has not been the case hitherto. The reason of this is, first, because the material so deposited from a state of suspension in the fluid is in the most porous possible arrangement, which, therefore, admits of the free passage of the steam through the material; and, secondly, because at the termination of the process of filtration a considerable portion of the liquid (which would be retained in the interspaces between .the particles of the residuum by capillary attraction if the liquid had been allowed to run away by gravitation solely) isforcedout by the expansion of the bisulphideof-carb'on vapor, which, under tension, had been the means of effecting the filtration, as already described. With these modifications the separation of the sulphur from spent oxide of iron is quickly and completely effected.

In case the spent oxide of iron should contain too little of the coarser particles, I find it advisable to mix it with spentoxide containing a greater proportion, or with some inactive material of such a specific gravity, size, and shape as will confer the necessary porosity; but generally the material requires no such admixture. i

These improvements, applicable to the treatment of spent oxide, are also of value in treating substances such as some descriptions of sulphur ore, WJllCll, on being crushed for the pur pose of separating the sulphur by the process, produce much finely-divided mineral matter, and. should be adopted. when the process of filtration is difficult.

In order that my most fully understo efi'ect, I will procee hereunto annexed, signed more particularly for the treatment of spent oxide by means of bisulphide of carbon.

Figure 1 is an elevation, partly in section, of

ous to the bisulphide'of carbon; The particles being cemented together by the sulphur, I employ an. agitator, consisting of arms or blades turning on an axis, and made to work in the receptacle by any convenient means. I introeptacle a quantity of bisulon equal to twice the we ght of der treatment, taking care that such introduction of the bisulphide of carbon, does not occupy more than a few minutes, which, by the system of raising the bisulphide of carbon herein described, is readily effected, care having been taken to have the pipes from the receiver sufiiciently large. Having dis-, placed the air, as hereinbefore described, and

the top of the extractor, ntents, so as quickly to, lete solution of the sulphur,'. d there is then no tendency in the onsoliilated. Another modification is sometimes to remove the solution of sulphur f the bisulphide of carb effect the comp which effecte required from the de when the mate-' rial operated on consists to any considerable extent of fine particles, buse, on then at- 0 filter off the so tion of sulphur, the pores of the filter soon become filled with ineffectual. Numerous experiments have beentried with, different textile fabrics as a filtering medium, but without any advantage, as the pores in all become speedily choked.

I will now explain a method of working and forming a filter which I have found to ana very effectual manner. The principles upon which it is founded are the following:

First, when bodies of different sizes, but of the same or nearly the same specific gravity, are permitted to sink in a fluid of lesser grav I ity, the larger masses sink faster than the smaller, because they present less surface to the resistance of the fluid in proportion to their weight, and therefore the bodies will ar range themselves in the order of their. respective sizes, the larger being at the bottom.

d to describe the drawings Secondly, it is well known that such an arthe apparatus, omitting the condensers and rangement of solid matter is the best for the gasometer, which parts are shown separately formation of a filter-bed. Now, in order to form such a filter-bed in the extractor, I so tents thereof that the whole of the solid matter may be; brought into a state of suspension in the fluid. I then suddenly agitation and permit the solid matbside for about thirty minutes.

tanees the residuum in the extractor (which usually consists of particles from the size of a pea, or larger, to that of a fine, impalpahle powder) arranges itself in the best condition for filtration. ()n then openk under the filtering-bottom the solution of sulphur filters off without any difficulty, and very quickly. The filter should also be similarly formed from the residuum insoluble in the bisulphide of carbon before ,in elevation, partly in section, at Fig. 2. Fig. 3 is a plan, lso partly in section, of the apparatus, omitting the stills, which are shown separately in plan at Fig. 4:.

. a a are a pair of extractors.

cylinders of a convenient size, say eight feet in diameter, so constructed as to be safe up to a moderate pressure, say twenty pounds to the inch, (although so high a pressure is' never required,) and they should also. be able to. resist the atmospheric pressure when there is a vacuum within. There is a man-hole at a in the top of the cylinder, and another at a in the bottom. These man-holes and others used in the apparatus are closed with covers, which are screwed down against a face, and the joint is made vapor-tight by means of flour 'paste applied with a brush to ter to su shin gs h ave which show apparatus de- Y They are gineis set slowly to Work, turning the agitator the surfaceswhich come into contact; or a matter suspended in the solvent. At this strip of dough made of linseed-meal will also make a sound joint, and is better in cases the commencement of the operation 0t agitation, the agitator is stopped, and the pressure extractor is steam-jacketed at a, and the jacket has a safety-valve upon it at a. a is a wooden grating at the bottom of the extractor, It has an opening in it at a, corresponding with the bottom man-hole. Over the grating a a coarse linen cloth, a, is laid. It has a gasket minutes, and then the cock d on the pipe 61 is opened, and the solution of sulphur is forced out by the pressure of the vapor through the filter into the receiver 6, hereinafter described. This having been accomplished, a further quanhere it is also made to fit close by means of a gasket. a is a vertical axis within the extractor, and passing out through a stutfing-box at he top. This stuffing-box I pack with cotton, and I lubricate it with soft soap. Upon the axis a are curved arms a", which, when the axis revolves, pass over and close to the surface of the filter-cloth, stirring up the material resting upon it. a is a beveled wheel fixed on the top of the axis a and a is a pinion gearing with it, the axis of which pinion is driven by the steam-engine a. The exhaust steam of the engine is passed into the steamjackets, and aids in heating the vessels. at is a mercurial pressure-gage inserted into the top of the extractor, and capable of showing the pressure up to, say, thirty inches of mercury.

The spent oxide, having been first thoroughtractor as the vapor therein condenses, and is now repeated, except that the washings are but the spirit is made to return by the same pipe, 6, by which it entered, and is passed into a separate vessel, hereinafter described, proscribed. This having been done the extractor is opened, a' truck, h, is run under the bottom man-hole, and, the agitator being set to work, the spent material is rapidly discharged and conveyed away. The filter-cloth, which is now moist, is removedyit is replaced with a dry one, and then all is ready for working another charge.

The receiver for sulphur solution 6 is an iron scribed, into the extractor through the pipe I). I prefer to use twenty gallons of bisulphide for each hundred-weight of the charge of dry material, and the two together should about three-quarters fill the extractor. The steam is then admitted into the jacket, and the end, by which the solution is admitted, passes down a larger pipe, a, nearly to the bottom of the tank. This is to prevent any air-bubbles entering with the liquid rising through the water in the tank, as such air would carry up with it globules of solvent, and so a sensible loss would result. The solution stands in the pipe 6 with Water over it. Any globules of bisulphide carried up by the air through the Water, being confined within a'narrow space, coalesce and then sink again. There is, consequent] y, but very slight loss by evaporation at the surface. 0 c are indicating-floats, 7 showing the amount of sulphur solution in the and mixing the charge, the air-pipe 0 being at this time left open. Vapor is soon produced, and being much denser than air, and the heat being carefully applied, it mixes with it but slightly, and by far the greater part of the air is displaced, and escapes by the air-pipe c before the bisulphide vapor commences to come over. AS soon as this vapor issues at the mouth of the air-pipe the pipe is closed by the cock upon it. If it be thought worth while a small condensing-Worm may be fitted at the end of the air-pipe, to prevent, for the most part, the trifling loss of bisulphide vapor which otherwise takes place. After the aircock has been closed the heat is continued until a pressure of from five to ten inches of I; i are the stills. They are closed cylinders, similar to the extractors, with man-holes at the bottom. Theyhave double bottoms, and steam is admitted between the two by the pipe is, which also serves to supply steam to the jackets of the extractors, and to the steam-engines, which Work the stirrers in these vessels, and also in the stills. The stirrer in each still consists of a vertical axis, 6 with arms i 6 upon it. One of the arms is inclined, to plow up the time, say about one-quarter of an hour from without opening the air-cock. The operation lution is drawn oifinto the stills to be distilled.

i the deposited sulphur in a granular state, and

. m passes to the top of a second sulphur, and prevent it forming a cake at the i pipes of large diameter contained in a waterbottom of the still, and is so set as to keep the cistern, g and a stream of cold water is adbottom quite free from deposit. The other is mitted constantly at the bottom of this cistern curved, so as to act more eihciently to disby a pipe, g and drawn off at the top by an charge the sulphur at the end of the operaoverflow, g, which leads into a drain. The tion when the man-hole at the bottom is open. condensed bisulphide, together with the incon- The axes of the stirrers in the stills are carried and driven in the same way as those in the extractors, and t is the steam-engine by which they are actuated; it exhaust into the spaces at the bottoms of the stills. 4; are safety-valves on these steam-spaces. i are ipes bywhich the condensed water is drawn 0%. The distilling operation is conducted in the following manner: The still having been closed at the end of the last operation of distillation, the air is expelled from it through the air-pipe i which is left open at the end. This is done by admitting an incondensable mixture of bisulphide vapor and air,'which is kept stored in a gas-holder, l, and the gaseous mixture is led into the still by the pipe I, and it is caused to flow gently by removing some of the counterpoise-weights l of the gas-holder. As soon as the air is expelled the air-cock is closed, and the counterpoise-weights are restored. The still is then about one-half filled with sulphur solution by opening the cook 6 The heat is then applied, and the pipe i", leading from the still-head to the condenser m, is opened. The evaporation is carried on with care, to avoid priming into the condenser, by the aid of the mercury-gage i and observation through the sight-hole 11 which is glazed with talc. When the sulphur begins to be deposited the agitator is turned slowly to keep from the bottom of this condenser by thepipe 1 By abrancinq, from this pipe the gaseous mixture enters the gas-holder I, while the liquid flows into the pure-spirit receiver 1). The pure-spirit receiver 19 and the washingsreceiver 1' are two similar cylindrical vessels closed at the top, and provided with man-holes. The bisulphide is admitted to them and draw-n off from them by the pipes p and r which both connect with the rising pipe b,leading to the extractors. The spirit is, when required, forced up into the extractors by admittin g water, under pressure, at the top of the receiver by one or other of the pipes 19 1", and when it is desired that spirit should descend from the extractors into the washings-receiver it is permitted to do so by opening the cooks upon the spirit-pipe b, and also the cock r which allows water to flow out from the top of the washings-receiver into the drain. In a similar way, when the pure-spirit receiver is receiving spirit from the condenser, water is allowed to escape at the top of the receiver by the cook 19.

The gas holder is clearly sh own in the drawings, and as it is of ordinary construction, no further description of it is required. The bisulphide gas, as it may be called, enters by the pipe and is drawn off for use by the pipe 1 I prefer to employ bisulphide of carbon as the solvent; nevertheless light hydrocarbon oil maybe employed. These oils being lighter than water, some obvious modifications of the apparatus will be requiredi; and, further, for treatment with hydrocarbons of light gravity, as described in such cases where, on cooling, a considerable deposition of sulphur would take place, it is necessary to avoid the radiation of heat from the eduction-cock and pipe from the extractor by covering them externally with a suitable non conducting material, or by jacketing them, so as to afl'ord the facility of keeping them warm, where required, by means of steam or liquid bath. And in such cases it is further necessary either to run the solution of sulphur from the extractor directly into the still, or else to provide some means of mainespecially toward the end of the operation it is kept constantly at work, and its speed is then increased to prevent the formation of a non-conducting cake upon the still-bottom. When the process is complete and bisulphide vapor is no longer generated, steam is blown into the still by opening a cock on the branch 70 of the steam-pipe, so as effectually to separate the remaining solvent from the sulphur, and to sweep forward the vapor in the still into the condenser. The connection with the condenser is then closed,-and the still is opened. A truck is run beneath it, agitator being again set to work, the sulphur is rapidly discharged into the truck. The condenser m, into which, at the upper end, the bisulphide vapor passes, is constructed like a tubular boiler. There is a vapor space at each end, and these are connected by a number of small-iron tubes, which are surrounded with cold water admitted by the water-pipe n, and drawn off into a drain by the pipe 0. The condensed bisulphide runs out at the bottom of the condenser by the pipe m, which branches into two pipes, m and m tern at a temperature above that at which the sulphur would be deposited.

Having said invention, and the manner of performing the same, I would here remark that I do not claim the separation of sulphur by employing the bisulphide of carbon as a solvent in aclosed apparatus arranged for the purpose, and separating the products by distillation, which has frequently been proposed, but not hitherto successfully worked; but

The pipe 'm leads into the pure-spirit receiver p, hereinafter described, while the pipe condenser, q, consisting of a rectangular coil, of iron dens-able mixture of vapor and air, is led away taining the sulphur solution in the supply-cisthus described the nature of my substance in What I claim is 1. The hereinbefore-described improvement in the art of separating free sulphur from substances With which it is mixed which improvement consists in mixing the sulpl'mr-bearin provement consists earing substance in phide of carbon the mixture to the boiling-point, agitating it, stopping the agitation, and allowing the granutractor itself.

2. The hereinbefore-described improvement in the art of separating free sulphur from substances with which it is mixed; which improvement consists in mixing a charge of sulphur-bearing substances with bisulphide of carbon in a closed vessel or extractor, heating, agitating, filtering, and discharging the 'd contents; then subsequently admitting a fresh charge of bisulphide of carbon into the extractor, mixing itb uum remaining therein, allowing the contents subside; then discharging of sulphur-bearing substance.

4. The hereinbefore-described improvement in the art of separating free sulphur from substances with which it is mixed; which improvement consists in discharging the washings from the extractor through a pipe inclosed in a larger one, both extending nearly to the bottom of a receiver, and below the surfrom the first one, and applying the resultant SAML. H. JOHNSON. product to a fresh charge of sulphur-bearing substance, thus securing the strongest practi- Witnesses:

cable solution for evaporation. WILMER M. HARRIS,

8. The hereinbefore-described improvement JNo. DEAN,-

in the art of separating free sulphur from substances with which it is Both of N 0. l7 Gracechurch Street, London.

mixed,- which im- 

